Marking instrument



FIG. 1 is an exploded perspective view of a marking instrument showingmy new design;

FIG. 2 is a front view with the cap affixed.

FIG. 3 is a right side view,

FIG. 4 is a left side view,

FIG. 5 is a rear view,

FIG. 6 is a top view and

FIG. 7 is a bottom view.

The ornamental design for a marking instrument, as shown and described.